Analysis of Organic Microremains in Extramasticatory Occlusal Dental Grooves: An Interpretative Challenge in Past Contexts

ABSTRACT This case study addresses the interpretive intricacies of establishing a cause‐and‐effect relationship between organic microremains and extramasticatory use of the dentition as a “third hand,” particularly in the context of prehistoric thread‐making activities. The evidence derives from an occlusal groove on the mandibular right central incisor (Tooth 41) of a juvenile female (16–20 age‐at‐death) from Burial 117 at Castellón Alto , an Argaric Bronze Age site (1951–1703 cal bce ) in southeast Iberia (Granada, Spain). Analytical methods included scanning electron microscopy (SEM), backscattered electron (BSE) imaging, and energy dispersive X‐ray spectroscopy (EDS). Morphological traits, including fibrous and flexible appearance, and elemental composition—elevated carbon levels with detectable amounts of nitrogen, potassium, and sulfur—suggest a probable vegetal origin. This interpretation is further supported by the contrast between the Ca/P atomic ratio of the dental enamel (≈2.04), consistent with hydroxyapatite structure, and the elemental profile of the residues, which lack this mineral signature and instead display a dominant organic composition. Variability in particle morphology is consistent with differential stages of degradation, despite the favorable preservation conditions at the site. Interpretations remain tentative due to several limiting factors, including potential contamination, postmortem alteration, the absence of taxonomically diagnostic features, and a lack of comparative reference collections. Nonetheless, the spatial distribution, physical features, and chemical profiles of the residues are consistent with the incorporation of plant‐derived material during repeated contact between fibers and tooth enamel. These findings underscore the value of microanalytical techniques in assessing occupational markers of human dentition, while also exposing the methodological and interpretative limitations that currently hinder conclusive identification of past behaviors. Occlusal grooves hold potential as indicators of habitual activities, but their interpretive utility depends on integrated analytical strategies and expanded datasets. Further research is required to refine criteria for distinguishing anthropogenic residues from taphonomic noise in archaeological dental contexts.